Optical Lens, Optical Package Having the Same, Backlight Assembly Having the Same and Display Device Having the Same

ABSTRACT

An optical lens refracts and reflects a light to increase a luminance in a top direction of the optical lens and to decrease a luminance in a horizontal direction of the optical lens. The optical lens includes a central portion and a peripheral portion. The central portion has a convex shape. The peripheral portion has a concave shape. The peripheral portion surrounds the central portion. Therefore, power consumption and manufacturing cost are decreased.

CROSS-REFERENCE TO RELATED FOREIGN APPLICATION

This application is a divisional of U.S. application Ser. No.11/369,424, filed on Mar. 7, 2006, which in turn claims priority fromKorean Patent Application No. 2005-33364, filed on Apr. 22, 2005, thedisclosures of both of which are herein incorporated herein by referencein their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to an optical lens, anoptical package having the optical lens, a backlight assembly having theoptical lens and a display device having the optical lens. Moreparticularly, embodiments of the present invention relate to ahybrid-typed optical lens capable of covering a large screen, an opticalpackage having the optical lens, a backlight assembly having the opticallens and a display device having the optical lens.

2. Description of the Related Art

A liquid crystal display (LCD) device, in general, displays an imageusing optical and electrical characteristics of liquid crystals. The LCDdevice is a non-emissive typed display device, which requires a lightsource. The LCD device displays the image using an externally providedlight or an internally provided light from a light source in the LCDdevice.

An exemplary light source includes a cold cathode fluorescent lamp(CCFL), a flat fluorescent lamp (FFL), a light emitting diode (LED),etc.

The LED is essentially a point light source that has poor luminanceuniformity. In order to increase the luminance uniformity of the LED, anoptical lens covers the LED.

Optical lenses for covering the LED are classified into top illuminationtyped optical lenses and side illumination typed optical lenses. Whenthe top illumination typed optical lens covers the LED, a luminance ofthe light source is increased. However, the luminance uniformity of thelight source having the top illumination typed optical lens isdecreased. When the side illumination typed optical lens covers the LED,the luminance uniformity of the light source is increased. However, aportion of the light generated from the LED may leak from the sideillumination typed optical lens.

As a screen size of the LCD device is increased, the number of the lightemitting diodes is increased. However, when the number of the lightemitting diodes is increased, a power consumption and a manufacturingcost of the LCD device are increased.

In addition, size and thickness of the LCD device are also increased, asthe number of the light emitting diodes is increased.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a hybrid-typed opticallens capable of covering a large screen.

An embodiment of the present invention also provides an optical packagehaving the above-mentioned optical lens.

An embodiment of the present invention also provides a backlightassembly having the above-mentioned optical lens.

An embodiment of the present invention also provides a display devicehaving the above-mentioned optical lens.

An optical lens in accordance with an embodiment of the presentinvention refracts and reflects a light to increase a luminance in a topdirection of the optical lens and to decrease a luminance in ahorizontal direction of the optical lens. The optical lens includes acentral portion and a peripheral portion. The central portion has aconvex shape. The peripheral portion has a concave shape. The peripheralportion surrounds the central portion.

An optical package in accordance with an embodiment of the presentinvention includes a light emitting member and an optical lens. Thelight-emitting member generates a light. The optical lens refracts andreflects the light to increase a luminance in a top direction of theoptical lens and to decrease a luminance in a horizontal direction ofthe optical lens. The optical lens includes a central portion and aperipheral portion. The central portion has a convex shape. Theperipheral portion has a concave shape. The peripheral portion surroundsthe central portion.

A backlight assembly in accordance with an embodiment of the presentinvention includes a substrate, a light emitting diode, an optical lensand a reflecting plate. The light emitting diode is on the substrate togenerate a light. The optical lens refracts and reflects the light toincrease a luminance in a top direction of the optical lens and todecrease a luminance in a horizontal direction of the optical lens. Theoptical lens includes a central portion and a peripheral portion. Thecentral portion has a convex shape. The peripheral portion has a concaveshape. The peripheral portion surrounds the central portion. Thereflecting plate is interposed between the light emitting diode and theoptical lens to reflect a portion of the light leaked from the opticallens.

A display device in accordance with an embodiment of the presentinvention includes a display panel and a backlight assembly. The displaypanel displays an image using a light. The backlight assembly includes alight emitting diode and an optical lens. The light emitting diodegenerates a light. The optical lens refracts and reflects the light toincrease a luminance in a top direction of the optical lens and todecrease a luminance in a horizontal direction of the optical lens. Theoptical lens includes a central portion having a convex shape, and aperipheral portion having a concave shape.

According to an embodiment of the present invention, the optical lens ofthe button type is a hybrid typed optical lens having a top illuminationtype and a side illumination type where the area covered by the one LEDis increased. Therefore, the power consumption and a manufacturing costof the backlight assembly are decreased, although the display device hasthe large screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an optical lens of a button type inaccordance with an embodiment of the present invention;

FIG. 2 is a cross-sectional view showing a light path through theoptical lens shown in FIG. 1;

FIG. 3 is a cross-sectional view showing a curvature of the optical lensshown in FIG. 1;

FIG. 4 is a cross-sectional view showing a size of the optical lensshown in FIG. 1;

FIGS. 5A to 5C are images showing optical simulations of the opticallens having various thicknesses;

FIG. 6 is a graph showing a relationship between a light extraction anda height of a wing of the optical lens shown in FIG. 1;

FIG. 7 is a graph showing a relationship between an orientation angleand a light extraction of the optical lens shown in FIG. 1;

FIG. 8 is an image showing an optical simulation of the optical lensshown in FIG. 1 when an optical system of the optical lens is about 20mm;

FIG. 9 is a perspective view showing an optical lens of a bowl type inaccordance with another embodiment of the present invention;

FIG. 10 is an image showing an optical simulation of the optical lensshown in FIG. 9;

FIG. 11 is an image showing an optical simulation of the optical lensshown in FIG. 1 when an optical system of the optical lens is about 40mm;

FIG. 12 is a graph showing a relationship between a light extraction anda thickness of the optical lens shown in FIG. 1;

FIG. 13 is a partial cutout perspective view showing a backlightassembly in accordance with an embodiment of the present invention; and

FIG. 14 is an exploded perspective view showing a display device inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Embodiments of the invention are described more fully hereinafter withreference to the accompanying drawings, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein.

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an exemplary optical lens of abutton type in accordance with an embodiment of the present invention.FIG. 2 is a cross-sectional view showing a light path through theexemplary optical lens shown in FIG. 1.

Referring to FIGS. 1 and 2, the optical lens 10 of the button typeincludes a central portion 12 and a peripheral portion 14. A recess 16is formed on a bottom surface of the central portion 12 to receive alight-emitting element such as a light emitting diode (LED). The recess16 has a shape corresponding to the light-emitting element. A lightgenerated from the light emitting element is incident into the opticallens 10 so that a central light exits from surfaces of the centralportion 12 and a peripheral light exits from surfaces of the peripheralportion 14. The light incident into the optical lens 10 is refracted andreflected where an intensity of the central light is decreased, and anintensity of the peripheral light is increased, thereby increasing aluminance uniformity. That is, the optical lens 10 increases theluminance in the top direction, and decreases the luminance in thehorizontal direction. When a size of the optical lens 10 is increased,an area covered by the optical lens 10 is increased.

The central portion 12 has a convex shape protruded in a top direction(z-direction). The central portion 12 has a substantially circular shapewhen viewed on a plane (x-y plane). The central portion 12 is defined bya plurality of curved surfaces having various curvatures. For example,the central portion 12 may function as a convex lens. Contour lines ofthe central portion 12 may be substantially parallel with each other.Alternatively, the contour lines of the central portion 12 may beshifted toward a predetermined direction. That is, a portion of thecontour lines may be denser than a remaining portion of the contourlines.

The peripheral portion 14 has a concave shape to receive the centralportion 12, and surrounds the central portion 12. In particular, theperipheral portion 14 has the concave shape in the top direction(z-direction). The peripheral portion 14 may have a substantially donutshape surrounding the central portion 12 when viewed on the plane (x-yplane). The peripheral portion 14 is defined by a plurality of curvedsurfaces having various curvatures. The peripheral portion 14 mayfunction as a concave lens. Contour lines of the peripheral portion 14may be substantially parallel with each other. Alternatively, thecontour lines of the peripheral portion 14 may be shifted toward apredetermined direction. That is, a portion of the contour lines may bedenser than a remaining portion of the contour lines.

The central portion 12 may be integrally formed with the peripheralportion 14. For example, the optical lens 10 includes apolymethylmethacrylate (PMMA) based resin. A refractive index of thePMMA based resin is about 1.5.

Referring again to FIG. 2, a first light path PATH1 and a second lightpath PATH2 are depicted in the central portion 12. The central portion12 guides the first and second light paths PATH1 and PATH2 to diffusethe light exiting from the surface of the central portion 12.

In particular, a first exiting angle θ1 t of the first light path PATH1is greater than a first incident angle θ1 i of the first light pathPATH1. In Snell's law, the central portion 12 has a greater refractiveindex than an air so that the first light path PATH1 is refracted todiffuse the light exiting from the surface of the central portion 12,thereby increasing the first exiting angle θ1 t.

In addition, a second exiting angle θ2 t of the second light path PATH2is greater than a second incident angle θ2 i of the second light pathPATH2.

A luminance of the light generated from a central portion of the LED isgreater than that of the light generated from a peripheral portion ofthe LED. In order to increase the luminance uniformity, the shape of theoptical lens 10 is adjusted to decrease the luminance of the lightgenerated from the central portion of the LED, and to increase theluminance of the light generated from the peripheral portion of the LED.In FIG. 2, the central portion 12 has a V-shaped recess to decrease theluminance of the light generated from the central portion of the LED,and to increase the luminance of the light generated from the peripheralportion of the LED.

A light passing through the third light path PATH3 is totally reflectedfrom the concave surface of the peripheral portion 14, and exits from aside surface of the optical lens 10. That is, when the light isirradiated onto the concave surface of the peripheral portion 14 at athird incident angle θ3 i, the light is then totally reflected from theconcave surface of the peripheral portion 14 at a reflection angle θ3 rthat is substantially same as the third incident angle θ3 i. Thereflected light is irradiated onto the side surface of the optical lens10 at a fourth incident angle θ4 i to exit from the side surface at afourth exiting angle θ4 t.

The first and second light paths PATH1 and PATH2 correspond to a topemission typed optical lens. The third light path PATH3 corresponds to aside emission typed optical lens. Therefore, the optical lens 10 ofFIGS. 1 and 2 has a hybrid typed optical lens having the top and sideemission typed optical lenses.

FIG. 3 is a cross-sectional view showing a curvature of the exemplaryoptical lens shown in FIG. 1.

Referring to FIGS. 1 to 3, the central portion 12 has the convex shapehaving the recess on a center of the central portion 12. The convexshape having the recess is defined by the curved surfaces having variouscurvatures.

For example, the central portion 12 includes a first curved surface, asecond curved surface, a third curved surface, a fourth curved surfaceand a fifth curved surface. The first curved surface is on the center ofthe central portion 12, and has a first radius of curvature of about2.76 mm. A center of the first radius of curvature is under the firstcurved surface. That is, the first curved surface is protruded toward afront of the optical lens 10. The second curved surface is adjacent tothe first curved surface and connected to the first curved surface, andhas a second radius of curvature of about 1.98 mm. A center of thesecond radius of curvature is under the second curved surface. The thirdcurved surface is adjacent to the second curved surface and connected tothe second curved surface, and has a third radius of curvature of about2.15 mm. A center of the third radius of curvature is under the thirdcurved surface. The fourth curved surface is adjacent to the thirdcurved surface and connected to the third curved surface, and has afourth radius of curvature of about 4.07 mm. A center of the fourthradius of curvature is on the fourth curved surface. That is, the fourthcurvature is protruded toward a rear of the optical lens 10. The fifthcurved surface is adjacent to the fourth curved surface and connected tothe fourth curved surface, and has a fifth radius of curvature of about22.97 mm. A center of the fifth radius of curvature is on the fifthcurved surface. The first, second, third, fourth and fifth curvedsurfaces define the convex shape having the recess. Note that the radiipresented in this paragraph are exemplary and non-limiting, and otherradii of curvature are within the scope of an embodiment of theinvention.

The peripheral portion 14 includes a sixth curved surface and a seventhcurved surface. The sixth curved surface is adjacent to the fifth curvedsurface and connected to the fifth curved surface, and has a sixthradius of curvature of about 13.74 mm. A center of the sixth radius ofcurvature is on the sixth curved surface. The seventh curved surface isadjacent to the sixth curved surface and connected to the sixth curvedsurface, and has a seventh radius of curvature of about 2.70 mm. Acenter of the seventh radius of curvature is on the seventh curvedsurface. The sixth and seventh curved surfaces define the concave shape.Note that the radii presented in this paragraph are exemplary andnon-limiting, and other radii of curvature are within the scope of anembodiment of the invention.

In FIGS. 1 to 3, the recess is formed on the center of the centralportion 12. Alternatively, the recess may not be formed on the center ofthe central portion 12.

In FIGS. 1 to 3, one LED corresponds to one optical lens 10.Alternatively, a plurality of light emitting diodes may correspond toone optical lens.

FIG. 4 is a cross-sectional view showing an exemplary, non-limiting sizeof the optical lens shown in FIG. 1.

Referring to FIG. 4, a radius L1 of the optical lens 10 may be about 6mm, and a maximum height T1 of the optical lens 10 may be about 3.6 mm.In addition, a maximum height T2 of the central portion 12 may be about3 mm.

A radius L2 of the central portion 12 may be about 3.5 mm. A height T3of a boundary between the central and peripheral portions 12 and 14 maybe about 2.1 mm. The height T3 of the boundary is a minimum height ofthe optical lens 10. The maximum height T2 of the central portion 12 issmaller than the maximum height T1 of the optical lens 10.

A height of an outmost portion of the peripheral portion 14 is themaximum height T1 of the optical lens 10. A size of the optical lens 10may be changed. The radius L1 and the maximum height T1 of the opticallens 10, the radius L2 and the maximum height T2 of the central portion12, and the height T3 of the boundary may be substantially proportionalto each other. For example, when the size of the optical lens 10 isincreased, the radius L1 and the maximum height T1 of the optical lens10, the radius L2 and the maximum height T2 of the central portion 12,and the height T3 of the boundary may also be increased.

FIGS. 5A to 5C are images showing optical simulations of exemplary 211optical lenses having various thicknesses. The maximum thickness of theoptical lens shown in FIG. 5A is about 3.7 mm. The maximum thickness ofthe optical lens shown in FIG. 5B is about 4.1 mm. The maximum thicknessof the optical lens shown in FIG. 5C is about 4.5 mm.

Referring to FIGS. 5A to 5C, the optical lens having the maximumthickness of about 3.7 mm has a substantially same optical distributionas the optical lens having the maximum thickness of about 4.1 mm.However, when the maximum thickness of the optical lens is more thanabout 4.5 mm, a light extraction of a center of the optical lens isdecreased, thereby decreasing a luminance on the center of the opticallens.

FIG. 6 is a graph showing a relationship between a light extraction anda maximum height of a central portion of the exemplary optical lensshown in FIG. 1. Light extractions of a top direction (z-direction) anda side direction (x-y direction) are shown in FIG. 6.

Referring to FIG. 6, when the maximum height of the central portion isabout 3.0 mm, the light extractions in the top direction and the sidedirection are about 84% and about 12%, respectively, and an averagelight extraction of the optical lens is about 96%. When the maximumheight of the central portion is about 3.55 mm, the light extractions inthe top direction and the side direction are about 83.56% and about13.61%, respectively, and an average light extraction of the opticallens is about 97.17%.

In FIG. 6, a light leakage from the optical lens is no more than about3% so that the optical lens may be optimized to a backlight assembly.

When the maximum height of the central portion is about 4.5 mm, thelight extractions in the top direction and the side direction are about77.91% and about 16.2%, respectively, and an average light extraction ofthe optical lens is about 94.11%.

When the maximum height of the central portion is about 4.5 mm, theoptical lens can also be used for the backlight assembly, although thelight leakage from the optical lens is about 5.89% that is negligible.

When the maximum height of the central portion is about 3.7 mm, thelight extractions are maximized. In FIG. 6, variations of the lightextractions of the optical lens having the maximum height of the centralportion of no more than about 3.7 mm may be negligible.

FIG. 7 is a graph showing a relationship between an orientation angleand a light extraction of the exemplary optical lens shown in FIG. 1. Inparticular, orientation angles in a top direction and a horizontaldirection are shown in FIG. 7.

Referring to FIG. 7, the orientation angle of the optical lens in thetop direction is from about −60° to about +60°. An orientation angle inthe top direction of an optical lens of a bowl type is from about −50°to about +50°. Therefore, the optical lens shown in FIG. 1 diffuses thelight in a wider range than the optical lens of the bowl type.

The orientation angle of the optical lens in the side direction is fromabout −80° to about +80°. The light exiting from the optical lens in theside direction may have a substantially same luminance as the lightexiting from the optical lens in the top direction corresponding to theorientation angle of about −50° or about +50°.

The light passes through the optical lens of the button type shown inFIG. 1 in the top direction and the side direction so that the opticallens may be a hybrid typed optical lens.

FIG. 8 is an image showing an optical simulation of the exemplaryoptical lens shown in FIG. 1 when an optical system of the optical lensis about 20 mm. Light extractions in the top direction and thehorizontal direction are shown in FIG. 8.

Referring to FIG. 8, the optical lens covers an area having a radius ofabout 38 mm. When an optical system of the optical lens of the bowl typeis about 20 mm, the optical lens of the bowl type is about 20 mm.Therefore, the radius of the region covered by the optical lens shown inFIG. 1 is greater than that of the region covered by the optical lens ofthe bowl type by about 90%.

Hereinafter, the optical lens having the bowl shape is described.

FIG. 9 is a perspective view showing an optical lens of a bowl type inaccordance with another embodiment of the present invention. FIG. 10 isan image showing an optical simulation of the optical lens shown in FIG.9. A distance between the optical lens of the bowl type and a lightsensor is about 40 mm, and an angle for sensing the light is about 70°.

Referring to FIGS. 9 and 10, a center of the optical lens 20 of the bowltype is protruded. Reference numerals 22 and 24 represent a wing portionand a guiding portion of the optical lens 20 of the bowl type,respectively. A recess 26 is formed on the guiding portion 24 to receivean LED.

Referring again to FIG. 10, the optical lens 20 of the bowl typeoptically covers an area having a radius of about 42 mm. A luminance israpidly decreased in a remaining area that is not covered by the opticallens 20 of the bowl type. In addition, a luminance of a central portionof the optical lens 20 of the bowl type is smaller than that of aperipheral portion of the optical lens 20 of the bowl type.

FIG. 11 is an image showing an optical simulation of the exemplaryoptical lens shown in FIG. 1 when an optical system of the optical lensis about 40 mm. Luminances in the top direction and the horizontaldirection are shown in FIG. 11.

Referring to FIG. 11, the optical lens shown in FIG. 1 optically coversan area having a radius of about 83 mm. The area covered by the opticallens shown in FIG. FIG. 1 is greater than the area covered by theoptical lens shown in FIG. 9 by about 97%. In addition, a radius of theoptical lens shown in FIG. 9 is about 20 mm, and a radius of the opticallens shown in FIG. 1 is about 6 mm. That is, the area covered by theoptical lens shown in FIG. 1 is increased although the radius of theoptical lens shown in FIG. 1 is decreased.

Therefore, the optical lens of the button type shown in FIG. 1 opticallycovers the large area so that a large screen display device may includethe optical lens of the button type shown in FIG. 1.

FIG. 12 is a graph showing a relationship between a light extraction anda thickness of the optical lens shown in FIG. 1.

Referring to FIG. 12, a maximum height of the optical lens of the buttontype shown in FIG. 1 is about 3.7 mm. When the maximum height of theoptical lens is no more than about 3.7 mm, the light extraction may benegligible. That is, the maximum height of the optical lens may bechanged to be no more than about 3.7 mm.

According to an embodiment of the invention, an optical lens of thebutton type is a hybrid-typed optical lens having a side illuminationtype and a top illumination type. That is, the light extraction and theluminance uniformity of the optical lens of the button type areincreased.

In addition, the area covered by the optical lens of the button type isgreater than the area covered by the bowl type by about 97%. The lightleakage of the optical lens of the button type is substantially same asthe light leakage of the optical lens of the bowl type so that the lightleakage of the optical lens of the button type is negligible.

FIG. 13 is a partially cutout perspective view showing a backlightassembly in accordance with an embodiment of the present invention.

Referring to FIG. 13, the backlight assembly 100 includes an opticalpackage 110, a power supply substrate 120, a receiving container 130, areflecting plate 140 and a light-mixing member 150. The power supplysubstrate 120 supports the optical package 110. The receiving container130 supports the power supply substrate 120. The reflecting plate 140 isinterposed between the power supply substrate 120 and the opticalpackage 110. The light-mixing member 150 is on the optical package 110.

The optical package 110 includes a light emitting diode (LED) 112 and anoptical lens 114 of a button type, according to an embodiment of theinvention. The optical lens 114 of the button type includes a centralportion and a peripheral portion. The central portion of the opticallens 114 has a convex shape. The central and peripheral portions definea button shape. A light generated from the LED 112 is incident into theoptical lens 114 so that a central light and a peripheral light exitingfrom surfaces of the central and peripheral portions of the optical lens114. The light incident into the optical lens 114 is refracted andreflected so that an intensity of the central light is decreased, and anintensity of the peripheral light is increased, thereby increasing aluminance uniformity.

The power supply substrate 120 supports the optical package 110 tosupply the LED 112 with an electric power.

The receiving container 130 receives the optical package 110, the powersupply substrate 120 and the light-mixing member 150. The receivingcontainer 130 may include a bottom plate and a sidewall.

The reflecting plate 140 is interposed between the power supplysubstrate 120 and the optical package 110. A portion of the light leakedfrom the optical lens 114 is reflected from the reflecting plate 140toward the light-mixing member 150. The reflecting plate 140 may be asolid plate. Alternatively, the reflecting plate 140 may be a flexiblesheet.

The light-mixing member 150 is on the optical package 110 to increase aluminance when viewed in a top direction and a luminance uniformity. Thelight-mixing member 150 may include a plurality of diffusion particles.

FIG. 14 is an exploded perspective view showing a display device inaccordance with an embodiment of the present invention.

Referring to FIG. 14, the display device includes a backlight assembly100, a display unit 200, a top chassis 300, a rear case 400 and a frontcase 500.

The backlight assembly 100 includes a plurality of optical packages 110,a power supply substrate 120, a receiving container 130, a reflectingplate, a light mixing member 150 and optical sheets 160. The powersupply substrate 120 supports the optical packages 110. The receivingcontainer 130 supports the power supply substrate 120. The reflectingplate 140 is interposed between the power supply substrate 120 and theoptical package 110. The light-mixing member 150 is on the opticalpackage 110. The backlight assembly of FIG. 14 is same as in FIG. 13.Thus, the same reference numerals will be used to refer to the same orlike parts as those described in FIG. 13 and any further explanationconcerning the above elements will be omitted.

The optical packages 110 are on the power supply substrate 120. Forexample, each of the optical packages 110 generates a white light.Alternatively, the optical packages 110 may generate a red light, agreen light and a blue light, respectively, or a combination thereof.

A portion of the light generated from the optical packages 110 isreflected from the reflecting plate 140 toward the light mixing member150.

The light mixing member 150 is on the optical packages 110. The lightgenerated from the optical packages 110 and reflected from thereflecting plate 140 is mixed in an air layer on the optical packages110 by the optical packages 110. For example, the light mixing member150 mixes the red, green and blue lights generated from the opticalpackages 110.

The optical sheets 160 include a diffusion sheet 162 and a prism sheet164. The diffusion sheet 162 diffuses the light having passed throughthe optical package 110. The prism sheet 164 increases the luminancewhen viewed in a top direction. The prism sheet 164 may include abrightness enhancement film (BEF), a dual brightness enhancement film(DBEF), etc.

The receiving container 130 includes a bottom plate 132 and a sidewall134. The bottom plate 132 has an opening. The sidewall 134 is protrudedfrom sides of the bottom plate 132. The power supply substrate 120having the optical package 110, the reflecting plate 140, the lightmixing member 150 and the optical sheets 160 are received on the bottomplate 132 of the receiving container 130.

The display unit 200 includes a liquid crystal display (LCD) panel 210,a data tape carrier package (TCP) 220, a gate TCP 230 and an integratedprinted circuit board (PCB) 240. The display unit 200 may furtherinclude a plurality of data tape carrier packages and a plurality oftape carrier packages.

The LCD panel 210 includes an array substrate 212, a color filtersubstrate 214 and a liquid crystal layer (not shown). The arraysubstrate 212 includes a plurality of pixels. The color filter substrate214 corresponds to the array substrate 212. The liquid crystal layer(not shown) is interposed between the array substrate 212 and the colorfilter substrate 214.

The data tape carrier packages 220 are attached to a source side of thearray substrate 212. The gate tape carrier packages 220 are attached toa gate side of the array substrate 212. The data and gate tape carrierpackages 220 and 230 applies a driving signal and a timing signal to theLCD panel 210 to control the LCD panel 210.

One end portion of each of the data tape carrier packages 220 isattached to the source side of the array substrate 212, and another endportion of each of the data tape carrier packages 220 is attached to theintegrated PCB 240 where the LCD panel 210 is electrically connected tothe integrated PCB 240 through the data tape carrier packages 220. Thegate tape carrier packages 230 are attached to the gate side of thearray substrate 212 where the LCD panel 210 is electrically connected tothe integrated PCB 240 through the gate tape carrier packages 230. Theintegrated PCB 240 applies signals to the data and gate tape carrierpackages 220 and 230 based on externally provided electric signals.

The data and gate tape carrier packages 220 and 230 are backwardly bentalong the sidewall 194 of the receiving container 190 so that theintegrated PCB 240 is on a rear surface of the bottom plate 192 of thereceiving container 190.

The top chassis 300 is on the LCD panel 210 to fix the LCD panel 210 tothe receiving container 190. The top chassis 300 includes an openingthrough which a central portion of the LCD panel 210 is exposed. The topchassis 300 is combined with the receiving container 190 to fix thedisplay unit 200 to the receiving container 190.

The backlight assembly 100, the display unit 200 and the top chassis 300are received in the rear case 400. The front case 500 is on the topchassis 300. The rear case 400 is combined with the front case 500 tocomplete the display device.

According to an embodiment of the present invention, an optical lens ofthe button type is a hybrid typed optical lens having a top illuminationtype and a side illumination type where the area covered by the one LEDis increased. In addition, the central portion of the optical lens mayhave the convex shape including the recessed center. Therefore, thepower consumption and a manufacturing cost of the backlight assembly maybe decreased, although the display device has the large screen.

This invention has been described with reference to the exemplaryembodiments. It is evident, however, that many alternative modificationsand variations will be apparent to those having skill in the art inlight of the foregoing description. Accordingly, embodiments of thepresent invention embrace all such alternative modifications andvariations as fall within the spirit and scope of the appended claims.

1. A display device comprising: a display panel that displays an image;and a backlight assembly providing a light to the display panelincluding: an optical lens including a central portion having a convexshape, and a peripheral portion having a concave shape.
 2. The displaydevice of claim 1, wherein the backlight assembly further comprises adiffusion plate that diffuses the light having passed through theoptical lens.
 3. The display device of claim 1, wherein the backlightassembly further comprises a reflecting plate and a point light source,the reflecting plate interposed between the point light source and theoptical lens to reflect a portion of the light leaked from the opticallens.
 4. The display device of claim 1, wherein a height of a boundarybetween the central and peripheral portions is a minimum height of theoptical lens, and a height of an outmost side of the peripheral portionis a maximum height of the optical lens.
 5. The display device of claim4, wherein a minimum height of the peripheral portion is about 2.1 mm,and a maximum height of the peripheral portion is about 3.6 mm.
 6. Thedisplay device of claim 1, wherein the convex shape of the centralportion has a recessed center to decrease the luminance in the topdirection.
 7. The display device of claim 1, wherein a refractive indexof each of the central and peripheral portions is about 1.5.
 8. Thedisplay device, of claim 1, wherein the central portion has asubstantially circular shape when viewed in the top direction, and theperipheral portion has a substantially donut shape surrounding thecentral portion.
 9. The display device of claim 8, wherein a width ofthe donut shape of the peripheral portion is not less than a radius ofthe circular shape of the central portion.
 10. The display device ofclaim 1, wherein the convex shape of the central portion comprises aplurality of curved surfaces having various curvatures, and the concaveshape of the peripheral portion comprises a plurality of curved surfaceshaving various curvatures.
 11. The display device of claim 10, whereinthe convex shape of the central portion has a recessed center, and thecentral portion includes: a first curved surface adjacent to therecessed center having a first radius of curvature of about 2.76 mm, acenter of the first radius of curvature being under the first curvedsurface; a second curved surface adjacent to the first curved surfacehaving a second radius of curvature of about 1.98 mm, a center of thesecond radius of curvature being under the second curved surface; athird curved surface adjacent to the second curved surface having athird radius of curvature of about 2.15 mm, a center of the third radiusof curvature being under the third curved surface; and a fourth curvedsurface adjacent to the third curved surface having a fourth radius ofcurvature of about 22.97 mm, a center of the fourth radius of curvaturebeing on the fourth curved surface.
 12. The display device of claim 10,wherein the peripheral portion comprises: a fifth curved surfaceadjacent to the central portion having a fifth radius of curvature ofabout 13.74 mm, a center of the fifth radius of curvature being on thefifth curved surface; and a sixth curved surface adjacent to the fifthcurved surface having a sixth radius of curvature of about 2.70 mm, acenter of the sixth radius of curvature being under the sixth curvedsurface.
 13. The display device of claim 10, wherein a radius of thecentral portion is about 3.5 mm, and a width of the peripheral portionis about 2.5 mm.
 14. The display device of claim 10, wherein a recess isformed on a bottom surface of the central portion to receive a pointlight source.
 15. The display device of claim 14, wherein the pointlight source makes contact with the central portion in the recess. 16.The display device of claim 14, wherein the point light source is spacedapart from the central portion in the recess to form an air layerbetween the point light source and the central portion.
 17. The displaydevice of claim 1, wherein an orientation angle of the light havingpassed through the optical lens in the top direction is from about −60°to about +60°.
 18. The display device of claim 1, wherein an orientationangle of the light having passed through the optical lens in the sidedirection is from about −80° to about +80.
 19. The display device ofclaim 10, wherein the central portion refracts the light.
 20. Thedisplay device of claim 10, wherein the peripheral portion reflects thelight.